Highly Resolved Runoff Path Simulation Based on Urban Surface Landscape Layout for Sub-Catchment Scale

The present study explored the regularities of the path and network structure of surface runoff formed under the influence of urban surface landscapes. We used unmanned aerial vehicle sensors to examine terrain and land use/cover change. The sub-catchments of a typical city, Luohe, China, were evaluated for the effect of landscape on surface runoff. Landscape and topographic parameters from 166 urban sub-catchments in Luohe were obtained by measuring digital surface models and orthophoto maps. The minimum cumulative resistance model was used to simulate potential runoff and 491,820 potential runoff paths, connected upstream and downstream, were obtained in 166 sub-catchments. The chi-square test was used to compare simulation runoff paths and actual runoff depth, with the results showing that they led to the same distribution trend. When the gravity coefficient was greater than 18.93, path disconnection occurred among 166 sub-catchments, with a decrease in channels. The potential runoff distribution appeared in aggregation; as the gravity coefficient increased from low to high, aggregation showed a trend of increasing initially but subsequently decreasing. The initial runoff formed sub-catchments with high gravity coefficients, then accumulated and spread to the others. It is important that proper measures are taken to establish a unified planning of the city’s surface landscape in order to produce suitable surface runoff distribution.